Timing control for oil burners and the like



April 1937- G. TOWNSEND 2,078,109

TIMING CONTROL FOR OIL BURNERS AND THE LIKE Filed Nov. 2, 1931 mafar George R Townsehd;

b5 Wm H is AUZOTTTEH.

Patented Apr. 20, 1937 UNITED STATES PATENT OFFICE George R. Townsend, Schenectady, N. Y., assignor to General New York Electric Company, a corporation of Application November 2, 1931, Serial No. 572,526

15 Claims.

My invention relates to timing control devices and has for its principal object a multiple interval automatic timing control device for a burner for fluids, although it is readily applicable to other uses.

The present invention is an improvement of the device set forth in my Patent No. 1,986,031 of January 1, 1935.

In the invention disclosed in my copending application, referred to above, a timing device termed a recycling mechanism opens and closes the fuel supply motor circuit and ignition system circuit at short intervals. The purpose of such an operation is to present several opportunities for igniting the oil spray.

When the flame is established, a heat responsive device or flame detector placed in the combustion chamber and actuated by the flame cuts out the ignition system and locks in the fuel supply motor. This flame detector may also be placed in the stack.

Should the flame fail during operation of the burner, the flame detector'energizes the recycling mechanism to re-ignite the oil by reenergizing ignition and fuel supply established by the recycling device. This is accomplished by the setting of the recycling mechamsm.

The flame detector referred to above is of a type commonly used and is a switch mechanism which responds to the flame within the combustion chamber to make and break certain circuits for controlling operation of the ignition system and fuel supply motor. A switch arm is mounted upon a shaft to rotate between a pair of contacts and is operated 'by means of a thermostatic element responsive to combustion conditions and placed within the combustion chamber. The switch arm is driven by means of the thermostatic element through a friction clutch mechanism so that the thermostatic element may continue to expand or contract after the switch'arm has reached either limit. Due to this construction employing the friction Connection between the thermostatic element and the switch blade upon cooling or upon heating of the thermostatic element, the switch arm is immediately moved from one contact to the other.

There is one difficulty experienced, however, with this type of flame detector. Should a flame be established for a sumcient length of time to cause the flame detector to deenergize the igni- This will result in pumping a large amount of oil into the fire box of the furnace which is an undesirable feature.

The reason for this is that the thermostatic element on the switch has been heated to a level ightly greater than the ambient temperature of the air surrounding the burner and yet sufliciently high to operate the switch to cut off the ignition system. Due to the small difierence in temperature between the thermostatic element and the surrounding atmosphere the rate of the heat dissipation by radiation is very slow. This causes the contact of the switch to be opened and to reset only after a relatively long period of time. This particular objection is not present after the flame in the burner has been established temperature of the thermostatic element and the surrounding atmosphere is great enough to cause rapid dissipation of heat. Upon cooling, the thermostatic element untwists rapidly and causes the switch to move to the cool position in a very short time.

Hence, it is a principal object of my invention to provide an oil burner control which will prevent flame failure immediately after combustion has been established.

More specifically it is an object of my invention to provide a tion.

In the preferred embodiment of my invention I provide a mechanism which is brought into operation upon establishing combustion to maintain the ignition system energized for a short period of time after combustion is established. Thus, if shortly after establishing combustion just sufficiently long to raise the flame detector to a temperature level slightly above surrounding The diiference between the.

period of post ignition after'es tablishing a flame to insure continued combuspivoted members so that the I The drawing shows a schematic diagram of my invention.

An oil burner furnace is has mounted adjacent thereto the fuel supply motor and blower l l. The fuel spray is ignited by means of the electrodes 92 which are energized by means of the ignition transformer dd. A thermostatic element l3 placed within the combustion chamber operates the switch is to make contact on either the left or right contact marked hot and cold. This flame switch or flame detector controls apparatus to be described later. To protect the oil burner furnace against dangerous pressure conditions, a pressure safety switch ill is mounted in the boiler at the top of the furnace id. This switch controls the fuel supply motor and ignition circuits .to one side of the line.

The control panel proper nous motor is which is continuously energized from the supply line Li and L2 by means of conductors 68 and 58'. A time control switch designated generally at it is driven through reduction gearing llil by means of the synchronous iii.

The pivoted members ill and it are mounted on a shaft supported by the brackets l l9 and |2El attached to the back panel (not shown). These members are biased in a clockwise direction by means of the springs E23 and E22. The pivoted member l8 carries contadts ill and M2 electrically insulated from each other and from member it, and pivoted member l'l carries double contact H3. The cams lid and H5 with which the pivoted members have engagement operate the double contact H3 will be in contact with the lower contact M2 to place thermostat 20 in the controlling circuit or in contact with the upper contact Hi to place the thermostat it in the controlling circuit. These circuits will be traced below.

The driving shaft I60 upon which the cams M and H5 arerotatably mounted has fixed thereto the dial Isl. The cams are operably connected to the drive shaft use by means of the adjusting members I II! and H8 which releasably engage the dial IN. The adjusting members Ill and I I8 are connected to the cams for the purpose of shifting the position of the cams on the shaft with respect to each other to determine the time at which the contacts H3, H2, and M will be shifted with respect to each other. A stop member |2| connected to the back panel (not shown) and coacting with the lug on the pivoted member limits the clockwise movement of the pivoted members when the members are not in contact with the cams. does not form a part of thisappllcation but is described and claimed in my copending application Serial No. 399,835, filed October 15, 1929.

The cam shaft 24' carrying the recycling cams 2| and 22 and the driving gear 24 are supported on the pivoted frame 21 by arms 25 and 25sttached to the pivoted frame2l; .A spring 28 returns the cam shaft and cams to initial position, when the frame returns to inoperative position. The pivoted frame 21 has attached thereto an armature 30 which coopdrates with the stationary core 3|! and issupported by means of bearings, such as brackets 29 and 29' attached to a panel, not shown. A stop 3| attached to the back includes a synchropanel (not shown) limits counter-clockwise movement of armature 30 and frame 21. A starting coil 3| and its core 30' are mounted on the panel,

not shown. The starting coil 3|, when energized, pulls the armature 30, within the coil thus ro- '-'-'its lower end a member motor The time control mechanism tating the frame 2'5 in a clockwise direction to mesh the driving gear 26 with the pinion 23 which is driven from the synchronous motor 55 which thus rotates the cam shaft carrying the cams 2| and 22. This movement of the frame also brings the cams 2i and. 22 into operating engagement with the pivoted members ti and :36 carrying the fuel supply motor and ignition circuit contacts. The action of the cams and the circuits will be described below.

The member 26 carries a rigid member 32 of insulating material which engages the member 33 pivotally supported in the bracket 33' attached to a panel, not shown. The member 33 carries at 32 of insulating material which supports the current-conducting bridging member 33" carrying contacts for completing circuits to be described later. This bridging member shorts out the controlling thermostat and locks the starting coil 3| across the secondary of the transformer 83 as will be described. It will be seen that as the frame 27 is rotated to operative position the member 33 is likewise rotated in a clockwise direction to close the bridging member 33 upon the contacts 92 and 93 carried by brackets and 8t fastened tov a panel, not shown.

A holding coil 3 maintains the member 33 in its closed position during combustion conditions in the furnace. When combustion is established in the combustion chamber-of the furnace iii, the flame detector l3 simultaneously opens the circuit through the starting coil 3| to release the frame 21, and establishes a circuit through the holding coil 3 to maintain member 33 in the closed position. The action and circuits will be described in detail below.

The pivoted frame 21 carries at its left-hand end a member 35 of insulating material carrying the bridging member 36 carrying contacts cooperating With the contacts and Q5 carried by brackets 81 and 88 fastened to a panel, not shown, for completing a circuit through the ignition transformer 65 in a manner and by means of circuits to be described below. The member 35 is mounted on a U-shaped member 31 pivotally supported in brackets 38 and 38" attached to the frame 21 and is biased against the movable frame 21 and the stop 31 in a counter-clockwise direction by means of the biasing spring 38. The member 35 carries an L- haped finger 39 cooperating with a time delay mechanism which will be described below.

The intermittent energization of the fuel supply motor circuit is accomplished by means of the members 40 and 4| plvotally mounted in brackets 91 and 98 and'carrying thereon the contacts 42 and 43. The rotation of the recycling cams 2| and 22 cooperating with extending portions at the upper ends of the pivoted members causes the contacts to be opened and closed with a snap action; as follows.

The members 4|! and 4| carrying the circuitmaklng and breaking contacts 42 and 43 are pivoted in brackets 91 and 98 attached to the panel above referred to. Springs 40' and 4| shown intermediate the lower ends of members 40 and M bias these members in a counter-clockwise direction about their pivots. The upper ends of these members have portions bent outwardly to engage the cams 2| and 22 during operation. A stop member 43' attached to the panel coacts with the finger 99 on member 4| and prevents member 40 carries at its upper end a latch 44 pivoted to the member 40. This latch carries a downwardly extending finger 80 cooperating with the pin 45 mounted in the stationary bracket 9'! attached to the panel, not shown, and previously referred to. The upper portion of the member 40 carries a finger H as shown, which cooperates with the pin 45 to prevent the from rotating the member 40 in a counterclockwise direction past a predetermined point.

When the frame 27 is rotated in a clockwise direction to engage the pinion 23 and driving gear 24, the cam contacting portion of member 4|, which is spaced only a short distance from the cam surface of cam 2| when the frame 21 is in inoperative position, engages the raised portion of the cam, and is rotated in a clockwise direction about its pivot as the cam shaft moves in. Before the frame reaches its operative position, the cam engaging portion of member 40 is engaged at the bottom of a depression in the cam face 22 and is likewise rotated in a clockwise direction through a much smaller angle, however, than the member 4|. Both pivoted members, therefore, rotate through a small angle towith pin 45 and the latch slot in the member 33 and engages the member 33. Thus it will be seen that as the frame 21 is rotated to its operative rotated through a small angle in a clockwise direction, member 4| being rotated through a much greater angle than member 40.

After the pinion 23 and gear 24 are meshed and as the cam shaft is rotated in a counter-clockwise direction, the cam engaging portion of the member 40 rides upon the first tooth of the cam 22 40 in a clockwise direction, thus moving the contact 42 toward the contact 43 carried by the member 4|. Just as the upper portion of the tooth on the cam 22 is reached, the cam contacting portion of the member 4| drops into the first depression on the cam face of cam 2|. This permits the biasing spring 4| to rotate the member 4| in a counter-clockwise direction to close the contact 43 on the contact 42 with a snap action. This closes the circuit of the fuelsupply motor II, as will be described.

If flame is not established during this period while the contacts 42 and 43 are engaged, the cam shaft on continued rotation will cause the next depression on the cam 22 to move opposite the cam contacting portion of member 40. the cam contacting portion contacts with the surface of the However, since the movement ofthe member 4| is stopped when it contacts with the cam face of cam 2|, the contacts 42 and 43 open as the member 40 continues to rotate until it abuts the stop pin 45. Upon continued rotation of the cam shaft the cycle just described is repeated, the cam engaging portion of member 4| having been engaged by the next raised portion on the cam 2| to rotate member 4| in a clockwise direction.

After a predetermined number of intermittent operations of the fuel supply motor, the control panel including the recycling apparatus is renthe member 46, the contacts 02,

dered inoperative by means of a latch mechanism which must be manually reset to again place the control panel in operative position. This latch mechanism includes the member 46 which is pivotally mounted in a suitable bearing at 41. A biasing spring 48 tends to rotate this member about its pivot in a clockwise direction. A latch 49 pivotally attached thereto is provided with a finger 49' having a cut-away portion forming a horizontal shoulder in one edge at the end thereof which shoulder engages with a stationary member 50 attached to the panel (not shown) to maintain the member 46 in the position shown by preventing clockwise motion thereof. The member 46 carries an arm 15 insulated therefrom as shown at 15' which arm in turn carries the current-conducting bridging member 16 carrying contacts I02 and I03 cooperating with the contacts carried by brackets 89 and 85 for making a circuit to be described later. Thus in the position shown, which is the normal position for I03 on member 16 are in the closed position. The latch 49 has an extension 52 thereon which cooperates with -the element 53 carried by the driving gear 24. When the element 53 contacts with the arm 52 on the latch it rotates the latch in a clockwise direction releasing the latch from the retaining member 50. The biasing springs 48, then rotate the member 46 in a clockwise direction and open the contacts carried by the bridging member 18. The member 46 may again be placed in operative position by manually depressing the latch by means of the part 54.

When the frame 21 is rotated in a clockwise direction, the member 35 is moved so that the element 39 moves into a recess 58 in the member 55 forming part of the time delay mechanism. This member 55 is pivoted to the member 56 which, in turn, is pivoted to the stationary support 51 supported by the panel, not shown. A spring 60 biases the member 55 in a clockwise direction about its pivot'. A second biasing spring 6| attached to the panel tends to hold the member 56 against the stop 62. When the element 39 is moved back into the recess 58 the biasing spring 60 pivots the member 55 in a clockwise direction about its pivot. Thus the member 35 cannot return to its initial position without first moving the element 55 outwardly with it.

On the end of the element 55 is a rack portion 59 which cooperates with the pinion 23 when it is forced into engagement therewith by the mem-' I ber 39 carried by member 35 which tends to return to its initial position when coil 3| is deenergized to permit the frame 21 to return to inoperative position. This movement of member 35 is not suflicient to open the bridging member 36 due to the wipe of the contacts carried thereby. The pinion 23 being constantly rotated causes the member 59 to move downwardly in a counterclockwise direction about its pivot until the element 39 is released from the slot 58. This permits the biasing spring 6| to return the elements and 56 to initial position and the element 35 to rotate in a counter-clockwise direction to its biased position against the stop 31'. Thus it will be seen that the contact carrying bridge member 36 is maintained in its closed position for a period depending upon the length of time required for the member 55 to disengage itself from the element 39. The frame 21 of course does not return to its initial position until combustion is established at which time the starting coil 3| is deenergized by the flame detector l3 in a manner me and its, thermostat 2e,

to be described to permit the frame 2! to rotate in a counter-clockwise direction to its inoperative position.

The various circuits will now be outlined. The primary of the transformer 53 is connected to the lines L1 and L2 by means of the conductors 65 and conductors t6 and 6?, which are connected to the contacts of the pressure-responsive device it which. is normally closed. Thus the transformer is constantly energizedexcept on voltage failure and when the pressure-responsive switch iii opens, the circuit to the side L2 of the supply lines.

Assuming the thermostat 2% to be closed on its left-hand contact, a circuit through the starting coil 3! can be traced as follows: From one side of the secondary of the transformer til, conductors H2, which is electrically connected to conductor E3, the double contact H3, which is electrically connected to conductor Hi, conductor id, to the current-conducting bracket 35, contact it'd, current-carrying bridging member 16, contact are, current-conducting bracket t9, conductors are and H, to the starting coil 3!, from the starting coil 3!, conductor 58, right-hand contact marked cold of the flame detector, which would be normally closed on starting the burner, switch arm i3, conductor 19, to the other side of secondary of the transformer 63.

The coil 3! being thus energized will rotate frame 21 by means of the armature 30 in a clockwise direction moving the member 33 clockwise to close the bridging member 33" on the contacts 92 and $3 to form a holding circuit for the coil 3!, which can be traced as follows: From one side of the secondary of transformer 63 through conductor i i, the current-carrying bracket 86, contact 93, bridging member 33", contact 92, current-carrying bracket 85, contact I03, bridging member l6, contact I02, bracket 89, conductors I06 and ill, to one side of the coil 3!, and from the other side of the coil 3! through conductor T8, the cold" contact of the flame detector. switch arm l3, conductor 59, to the other side of the transformer. Thus movement of the thermostat blade it] out of contact with its left hand contact will not affect the energization of the coil 3 I When the frame 2'! has been rotated in a clockwise direction, member 35 closes the current-carrying bridging member 36 on contacts 96 and 95 carried by the current-carrying brackets 87 and 88. Bracket 88 is electrically connected with pivoted member M. Ills energizes the primary of the ignition transformer 6% whose circuit may be traced as follows: From the line L1, conductor 68, to one side of the primary of the transformer, from the other side of the primary of the transformer, conductor 69, bracket 8?, contact 9Q, bridging member 36, contact 95, bracket 88, through the pivoted member ti, conductors 83 and 66, pressure-responsive switch Hi, conductor 61, to the other side of the line L2. The electrodes l2 are energized from the secondary of the ignition transformer ti by means of the conductors Hi and l I.

When the pivoted members All and ii are operated upon to close the contacts 2 and 3, a circuit for the fuel-supply motor H is completed through these pivoted members as follows: From the line L1, conductors 85, M to one side'of the motor H, from the other side of the motor H through conductor to the pivoted member to. through member 40, contacts 42 and 43, member closed position by means ondary of transformer conductor l3, contact I supply motor circuit is tated to move the ti, conductors 83, B6, to the pressure-responsive switch iii, conductor 61, to the other side of the line L This, of course, energizes the motor.

Upon establishing flame, the flame detector moves the switch arm it to the left-hand or hot contactthus opening the circuit through the starting coil 3i and closing a circuit through the holding coil M to maintain the member 33 in closed position and the contacts 52 and id in of the latch fi l connected to the pivoted member Q9. This circuit may m traced as follows: From one side of the sec- 63, through conductor it, bracket tia'contact 93, bridging member 33", contact 92, bracket 85, contact H13, bridging member it, contact Hi2, bracket 89, conductors Hi6 and we, to one side of the coil 3 3, from the other side of the coil 36, through conductor 82, the hot contact of the flame detector, switch arm i3, conductor W, to the other side of the secondary of transformer 63. In this way the fuelmaintained closed until the thermostat 20 calls for a shut-down.

The operation of the mechanical parts of my control apparatus will now' be briefly reviewed and the detailed circuits will be traced when describing the operation of the apparatus. Assuming the apparatus to be in the position shown on the drawing and that the controlling thermostat 2@ moves to close on the left-hand contact to call for heat, the starting coil 3! is energized from the secondary of the transformer 63 and rotates the frame 21 in a clockwise direction. This meshes the gears 2t and 23 and causes rotation of the cam shaft carrying the cams 2| and 22 which operatively engage members ill and d0 controlling the fuel supply motor circuit. At the same time the pivoted member 33 is robridging member 33 to its closed position to lock the starting coil 3i across the secondary of the transformer 63 and thus shorts out the starting side of the thermostat. The member 35 moves the bridging member 36 to closed position and completes the circuit through the primary of the ignition transformer 64. Thus the ignition transformer is energized.

The cams in rotating open and close the circuit through the fuel supply motor H intermittently until combustion is established by means of the spark playing between the electrodes l2 energized from the secondary of transformer t l. When flame is established, the thermostatic switch it, which makes a circuit through the starting coil 3! when in cold position responds to the flame and simultaneously opens its righthand contact and closes the left-hand contact. This deenergizes the starting coil 3i permitting frame 27 to return to inoperative position and energizes the holding coil 3% to hold the pivoted member 33 in its closed position. The latch 66 which cooperates with the top part of the pivoted member 33 maintains the pivoted members 60 and M in closed position thus locking the circuit to the fuel supply motor and maintaining it energized.

When the frame 21 is released and rotates in an anti-clockwise direction until stopped by the stop member 3i, the biasing springs 40' and ll tend to urge'the pivoted members 60 and M in a clockwise direction. The latch M, however, is connected to the pivoted member M and engagesfithe member 33 which is held in position with the bridging member 33" closed by means of the electro-magnet 38. This prevents the member to from moving in a counter-clockwise direction under the influence of spring 40'. Since the pivoted member 40 cannot move and since the contacts 42 and 43 are in engagement, the pivoted member 4| being biased against the pivoted member 40 is prevented from anti-clockwise rotation. Thus the contacts 42 and 43 are maintained closed.

When the coil 3| ls deenergized the frame 21 returns to its initial position demeshing gears 23 and 24 and carrying with it the cams 2| and 22 which are returned to initial position by spring 28. The member controlling the ignition circuit is maintained in its closed position as described above until released by the member 55. Thus the ignition system remains energized for a brief period after combustion is established.

If the several attempts are unsuccessful in producing combustion, the tripping mechanism referred to above is actuated to render the entire apparatus inoperative by opening one side of the secondary of the transformer 63 and thus'deenergizing coil 3 I. The general and specific functions and circuits of the various parts of the apparatus having been stated, a detailed description of the entire operation and circuits will now be described.

As shown, the thermostat 20 is in the control circuit in the secondary of transformer 63. The transformer 63 has the upper side of its primary connected to one side of the line L2 by means of conductor 66, safety pressure switch I0; and conductor 61. The other side of the primary is directly connected to the other side of the line L1 by conductor 65. The transformer 63 is constantly energized from lines L1 and L2 except during voltage failure or when switch I0 is opened .on excessive boiler pressures. When the thermostat blade moves to the left-hand contact marked cold to call for heat, a circuit is completed from the upper side of the low voltage winding of transformer 63 through conductors, I05, I08, thermostat 20, conductor 13, contacts I I2 and H3 of conductor 14, bracket 85, contact I03, bridging member 16, contact I02, bracket 89, conductors I06 and 11 to one side of the coil 3|; from the other side of the coil 3|, conductor 18, right-hand contact marked cold of the flame detector, switch arm l3, conductor 19 to the other side of the secondary of transformer 63. This energizes the coil 3| which draws its armature 30 within itself and pivots the frame 21 to which the armature is fastened in a clockwise direction to mesh the gears 24 and pinion 23 to drive the cam shaft.

The members 33 and 35 are rotated in a clockwise direction to closethe bridging members 33" and 36 as described above. When the bridging member 33" is moved to the closed position a circuit is completed from the upper side of the transformer 63, conductor 14', bracket 86, contact 93, bridging member 33", contact 92, bracket 85, contact I03, bridging member 16, contact I02, bracket 89, conductors I06 and 11, starting coil 3|, conductor 18, switch l3, conductor 19 back to the lower side of transformer 63. Thus it will be seen that the starting coil 3| is locked across the secondary of the transformer 63 and that thermostat 20 is shorted and has no further effect on the operation of the panel. Movement of the thermostat blade to its inactive position will not effect the further operation of the coil 3|.

At the same time a circuit is completed for the ignition system from one side of the line L1 by conductor 68, to one side of the primary of the ignition transformer 64, from the other side by conductor 69, bracket 81, contact 94, bridging member 36, contact 95, bracket 88, pivoted member 4| ,'conductor 83, conductor 66, the pressure safety switch I0, conductor 61 to the other side of the line L2. The secondary of the ignition transformer 64 is connected to the electrodes I2 by means of the conductors 10 and 1|. Thus, it will be seen that so long as the bridging member 36 is in closed position, the ignition system will be energized.

The circuit through the fuel supply motor which is made when the contacts 42 and 43 are in contacting positions can be traced from one of line L1, conductors 65 and 8| to one side of the motor II, from the other side of the motor I I through the conductor 80, through the pivoted member 40 through the contacts 42 and 43, pivoted member 4| and conductors 83 and 66, pressure safety switch I0, conductor 61 to the other side of the line L2.

If combustion is established during one of the periods when contacts 42 and 43 are closed, the thermostatic element I3 of the flame detector expands and moves the switch arm I3 from the right-hand contact to the left-hand contact making a circuit through the holding coil 34 before breaking thecircuit through the starting coil 3|. The circuit for the holding coil 34 may be traced from the upper side of the secondary transformer 63, conductor 14', bracket 86, contact 93, bridging member 33", contact 92, bracket 85, contact I 03, bridging member 16, contact I02, bracket 89, conductors I06 and I06, to one side of the coil 34, from the other side of coil 34, conductor 82, switch I3, conductor 19, to the lower side of the transformer 63. When the coil 3| is deenergized, the frame 21 returns to its inoperative position carrying with it the driving gear and the cams. The holding coil 34, however, holds the member 33 in its closed position and the member 55 temporarily maintains the member 35 in its closed position, as described above. The latch 44 which cooperates with the member 33 maintains the contacts 42 and 43 closed thus maintaining a circuit through the fuel supply motor I I. It will be seen that the coil 34 is across the secondary of the transformer 63 and will remain energized so long as the flame detector maintains the switch arm closed on the left-hand or hot contact.

As has been stated above, the ignition system is maintained energized for a brief period of predetermined duration after combustion is established to avoid the objections pointed out in the first part of the specification, that is, having the fiame extinguished before the thermostatic element I3 has attained a high temperature. As described above, the bridging member 36 is maintained in closed position until the member 55 of the time delay mechanism releases the element 39 carried by the member 35. When the arm 39 is released the spring bias 38 returns the arm 35 to its initial position abutting the stop 31' and the spring 6| returns the time delay mechanism to its initial position out of contact with the pinion 23.

When the thermostat 20 indicates that sufficient heat has been supplied, the blade 20 will close on the right-hand contact and short-circuit the secondary of transformer 63, thus deenergizing the holding magnet 34 and permitting the member 33 to return to ing the.bridging member 33" to open position. When the thermostat blade moves to the righthand contact, a circuit is completed from one side of the transformer, through conductor I01, thermostat 20, through'conductor 13, contacts .I2

inoperative position moving relationship 'termined period of time and MB of switch it, conductor ii-5, bracket 35, contact 92, bridging member 33", contact 83, bracket 86, conductor i i to the other side of transformer 63. As soon as bridging member 33" opens, the short across the transformer is broken. The control panel is thus placed in a position to again initiate combustion conditions when the thermostat calls for heat.

Although my invention is specifically applicable to oil burners, it is apparent that my invention can be used whenever it is necessary to control one device by a timing means for a variable period and when this period is determined to control another device by said timing means for an: other predetermined period of time.

The embodiment of the invention illustrated and described herein has been selected for the purpose of clearly setting forth the invention involved. It will be apparent, however, that the invention as discussed will be modified to meet the difierent conditions encountered in its use and I, therefore, aim to cover by the appended claims all modifications within the true scope and spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A timing-control device having a timed driving element, a control means, means for bringing said control means into and out of operating relationship with said timed driving element, means responsive to predetermined conditions for controlling said last means to bring said control means out of operating relationship with said timed driving element, a second control means, and'means rendered efiective when said first control means is brought out of operating relationship with said timed driving element for bringing said second control means into operatwith said timed driving element.

2. A timing-control mechanism for controlling circuits comprising a timing device, a means for controlling a circuit, means for bringing said circuit-controlling means into and out of operating relationship with said timing device, means responsive to predetermined conditions for controlling said last means to bring said circuit-controlling means out of operating relationship with said timing device, a second means for controlling a second circuit, and means for bringing said second circuit controlling means into operative engagement with said timing device for a prede after said first circuitcontrolling means is brought out of operating relationship with said timing device.

3. A timing device having a timed driving means, a circuit-controlling member adapted to be controlled thereby, a member for establishing operating connections between said timed driving means and said circuit-controlling memher, a second circuit-controlling member adapted to be controlled by said timed driving means, and means for operatively connecting said timed driving means and said second circuit-controlling means for placing said second circuit-controlling means under the control of said driving means for a predetermined period of time, and a device responsive to predetermined conditions for rendering said connecting member inoperative to maintain the operative connection between said first circuit-controlling member and said timed driving means and for thereafter rendering said connecting means operative to place said second circuit controlling means under the control of said timed driving means.

4. A timing control device having a timed drivaoraioc ing element, a circuit-controlling device, means for. bringing said circuit-controlling device into and out of operating relationship with said driving element, a second circuit-controlling device and a member adapted to bring said second circuit-controlling device into operating relationship with said timed driving element, and means responsive to predetermined conditions for causing said first circuit-controlling device to be brought out of operating relationship with said timed driving element and for thereafter rendering efiective said member for bringing said second circuit-controlling device into operating relationship with said timed driving element whereby said second circuit-controlling means is under the control of said timed driving element for a predetermined period of time.

5. A timing mechanism having a timed driving motor, a circuit-controlling member operable between two positions, a timing device adapted to have an operative relation with said timed driving motor for controlling operation oi said circuit-controlling member for a predetermined period of time, a means responsive to predetermined conditions for causing movement or" said circuitcontrolling member from one position to another position said circuit-controlling member bringing said timing device into operative relation upon movement of said circuit controlling member from one of said positions to another.

6. A. timing device having a timed driving means, a circuit-controlling member, means for moving said circuit controlling member into operative relationship with said driving means, a

second circuit-controlling member movable from one position to another position when said first circuit-controlling member is moved into operatlve relationship with said driving means, a device responsive to predetermined conditions for rendering said moving means ineffective to hold said first circuit-controlling member in operative relationship with said timed driving means, and means for maintaining said second circuit-controlling member in said other position for a predetermined period of time after said moving means becomes ineffective, said maintaining means being brought into operative relationship with said timed driving means to be controlled thereby when said moving means becomes inefiective.

7. Atiming device having a timed driving motor, a driving gear connected to be driven thereby, a switch, means for moving said switch from one position to another position, a cooperating rack mechanism adapted to be brought into engagement with said driving gear to be operated thereby means responsive to predetermined conditions for rendering said switch-moving means inefiective to hold said switch in said other position, and means on said switch cooperating with said racl: mechanism to bring the same into engagement with said driving gear when said switch moving means is rendereddnefiective, said rack mechanism thereafter maintaining said switch in said other position a predetermined period of time after said switch-moving means is rendered in eflective.

8. A timing device for an oil burner having a fuel supply motor and ignition system therefor, a timed driving means, a circuit-controlling means for the fuel-supply motor, means for brin ingsaid motor circuit-controlling means into and out of operating relationship with said timed driving means, a second circuit-controlling means for the ignition system, and a heat responsive device responsive to combustion for causing said motor circuit-controlling device to be brought out of operating relationship with said timed driving means, and means for bring said ignition circuitcontrolling device into operating relationship with said timed driving means when said motor circuit-controlling means is brought out of operating relationship with said driving element, whereby said ignition system is maintained energized a predetermined period after combustion is established.

9. A timing device for an oil burner for controlling post ignition having a timed driving means, an ignition circuit-controlling member, means for moving said circuit-controlling memher from open position to closed position, and a heat responsive device for rendering said moving means ineffective to hold said ignition circuit controlling means in closed position when flame is established, and means brought into operative relation with said timed driving means by said circuit controlling member when said moving means returns to the open position, for maintaining said circuit-controlling means in closed position for a predetermined period of time after flame is established.

10. A circuit controlling timing mechanism for an oil burner having a fuel supply motor and an ignition system therefor, a timing device, a control means for controlling the fuel supply motor, and means for bringing said control means into operating relationship with said timing device,

means responsive to combustion for controlling said last means whereby said motor-control means is brought out of operating relationship with said timing device, and a second control means for controlling the ignition system, and other means for bringing said second control means into operative relationship with said timing device for a predetermined period of time after said motor control means is brought out of operating relationship with said timing device.

11. A circuit-controlling timing mechanism for an oil burner having a fuel-supply motor and an ignition system, a timing device, a control means for controlling the fuel-supply motor and means for bringing said control means into and out of operative relationship with said timing device, means responsive to combustion conditions for controlling said last means to bring said motor control out of operating relationship with said timing device, a second control means for controlling the ignition system, and means for bringing said second control means into operative relationship with said timing device when said first control means is brought out of operative relationship with said timing device.

12. A circuit-controlling device for an oil burner having a fuel-supply motor and an ignition system, a timing motor, a circuit-controlling device for controlling energization of said fuelsupply motor to initiate combustion, means for bringing said circuit-controlling device into operative relationship with said timing motor, a control means for energizing said ignition system while said circuit-controlling device is in operative relationship with said timing motor, a second control device for controlling said ignition control means and means for bringing said second control device into operative relationship with said timing motor when the operative relationship between said timing motor and said circuit-controlling device is discontinued upon establishing combustion.

13. A circuit-controlling device for an oil burner having a fuel supply motor and an ignition system, a timing motor, a circuit controlling device for controlling energization of the fuel supply motor to initiate combustion, means for bringing said circuit controlling device into operative relationship with said timing motor, means carried by said means for bringing the circuit controlling device into operative relationship, for energizing said ignition system while said circuit controlling device is in operative relationship with said timing motor, a controlling device for controlling said ignition energizing means, said ignition controlling device being brought into operative relationship with said timing motor by said ignition energizing means when said motor circuit controlling device is brought out of operating relationship with said timing motor upon establishing combustion.

l4. Anoil burner control having a fuel supply motor, an ignition system therefor, a member movable between operative and inoperative positions carrying a device for energizing said ignition system and a second device for controlling intermittent operation of said fuel supply motor to establish combustion when said member is moved to operative position, a heat responsive device for deenergizing said ignition system and mantaining said motor energized upon establishment of combustion conditions, and a time delay device rendered operative upon establishment of combustion conditions for cooperating with said ignition energizing device to render said ignition system deenergizing device ineffective for a predetermined period after combustion is established.

15. An oil burner control having a fuel supply motor, an ignition system therefor, a frame movable between inoperative and operative positions, means carried by said frame for energizing said motor, a second means carried by said frame for energizing said ignition system to establish combustion when said frame is moved to operative position, and a heat responsive device for returning said frame to inoperative position and maintaining said fuel supply motor energized when combustion is established and a time delay device rendered operative when said frame returns to inoperative position for holding said ignition energizing means in operative position to maintain said ignition system energized for a predetermined period after combustion takes place.

GEORGE R. TOWNSEND. 

